DIRECTIONS:Preheat oven to 350 degrees F. and lightly grease a 9 X 5 inch loaf pan.In one bowl, mix together the flour, cocoa, baking powder, baking soda and salt.In a separate bowl, whisk together the yogurt, milk, and vanilla, then set aside.Cream the butter with the sugar for about 3 minutes or until light.Add the eggs one at a time beating well between each.Add the grated chocolate and stir, then half the flour and half the yogurt mixture and mix.Add the remaining yogurt and flour mixtures and mix just until combined.Pour the batter into your prepared pan and smooth the top.Bake for about 50 to 55 minutes or until a skewer inserted into the center comes out clean.Cool for 15 to 20 minutes then gently remove from the pan.Allow to cool to room temperature before slicing.If desired, the loaf can now be sprinkled with powdered sugar, or spread with the glaze of your choice.